Shock-absorber.



W. B. KNAPEL SHOCK ABSORBER. APPLICATION FILED AUG. 20, 1909.

' Patented Jan. 17, 1911.

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STjiTliihi it T WILLIAM BRUCE KNEEPP, OF STONEHAM, MASSrfiHUSETTS. ASSIGNOB T0 ANNIE L. KNAJPP, OF STONEHAZVI, LlVIASSACIliI/ SETTS.

SHOCLK-ABSC'RBER.

eseoos.

Speeifica tion of Letters Patent.

Patented Jan. 1?, 1911" Application filed August 20, 1309. Serial No. 513,731.

T 0 all whom it nary concern:

Be it known that l, WILLIAM B. Knarr, of Stoneham, county of 'Middlesex, State of Massachusetts, have invented an Improve ment in ShoclcAbsorbcrs, of which the folmeans for establishing open communication I between the opposite endeportions of the cylinder, permitting movement of the piston.

and cylinder toward and from each other, and having means for restraining such move ments.

The object of the invention is to provide the cylinder with a continuously .open main by-pass, permitting movements of the cylinder and'piston toward and from each other, and also with an improved form of antomatically-controlled by-passv by which movements of the cylinder and piston toward and from each otherare controlled in the following manner: Upon the occurrence of a feeble shock their movements toward each other will be'unrestrained and their return 1 movements restrained, and upon the occurrence of a violent shock their movements toward each other will be unrestrained during the first part of thost'roke, and gradually restrained during the last part thereof until checked. and their return movements will be unrestrained during the first part of thestroke and severely restrained during the last part thereof until checked.

The. invention also has for its object to movably connect the imperforate piston with the )iston-rod to provide for ashort indepen ent movement of said rod. which is of particular advantage upon the occurrence of feeble shocks hut is also of advantage at other times. I

Figure 1 is a longitudinal vertical section 01"- a shock-absorber embodying this invention. Fig. 2 is a cross-section of the shockabsorber shown in Fig. 1 taken on the dotted line 2-2f Fig. 3 is a sectional detail of the lower end-portion of the cylinder showing the lowermost port of the main by-pass. Fig. l-is a sectional detail of the lower end portion of the cylinder showingmodified the main hy-pass and automatically der another by-pass 0 forms of ports for the lower ends of both controlled by-pass.

As here shown a represents a hollow cylinder, closed at its ends. and Z) a piston containedtherein and attached to a piston-rod 6', which extends through a suilable stufiingbox If. The cylinder has a bypass connection between its upper and lower ends, comprising as here shown, two by-passes. Along the wall of the cylinder a, a. main by-pass a is formed or provided which extends from end to end of the cylinder or thereabout, which is open at both ends into said eylin der, and said bypass is provided with a manually operated regulating-valve The port a? leading from the upper end of the main bypass to the cylinder may be circular or of any other shape, and the port a leading from the lower end of the main by-pass to the cylinder may be made as an inverted triangle, see Fig. 3, having its upper end made substantially as wide as the lay-pass, and having its sides gradually converging toward the lower end, or said lower portmay be made as a long slot having parallel sides, see Fig; 4. .Also along the wall of the cylinis formedor provided, which extends from end to end of the cylinder or thereabout, which is adapted to be automatically controlled, and is employed for Eontrolling the movements of the cylin" der and piston toward and from each other. As shown in Fig. 1, said by-pass has several ports of various sizes, arranged along its length, all leading to the eylinder,as c, c c. 1 and c. At the upper endortion 0% said by-pass (f a check-valve (i, 0 any suitable construction, .is provided, which may be made as a cylinder or ball, and, as, here shown. said by-pass c has an enlargedportion provided with a seat d, on which said check-valve normallyrests, 'to'ciose the bypass. Said check-valve is moved by varia tions in pressure as the piston and cylinder are moved relatively to each other. The seat (5, is a rranged below the port 0 so that the checlrwal've. when seated, occupies a position opposite saidport 0 or thereabout. The,

portsc 0* and 0" are arranged at the lower end-portion of the bypass. As here shown, the port 0* is made of a lesser area than the port 0 and the port a of lesser area. than the port and thc distance between the :f)01i-S c and c" is less than the distance between the ports a and 0*, but the sizes oi the ports and their relative positions may be varied. Yet it'will be understood, that the combined areas of the three ports 0 0*, 0", shall be as. great or greater than the area of the port 0 and the combined areas of the ports 0 and 0 shall be less than the area of the port 0 i The lower end of the cylinder has a connection adapting it to be connected with the runninggear, and the piston-rod has at its extremity a connection adapting it to be connected with the frame. Said piston-rod, however, is preferably made to move a short distance without moving the piston,'as for il'lSl'Ltl'lCC upon the occurrence of a very feeble shock, and, as here shown, the piston is arranged loosely on, and so as to slide on the rod for a short distance. The piston-rod has its lower end formed with a reduced portion o and with shoulders I) and 7/", to thus provide for a short movement of the rod independently ot' the piston. By loosely connecting the piston to its red, ashore shown,

it will be observed that on a full stroke of the piston it will not strike against the lower end of the cylinder for the reason that the end ot'the piston rod projects below it for a short distance at such time.

Normally the piston i) occupies a position at or near the upper end of the cylinder, as shown in Fig. 1, and when the piston and cylinder are suddenly moved toward each other a short distance, due to a feeble shock, the check-valve in the lay-pass 0 opens, and the liquid oonlaincd in the cylinder is forced through the main by-pass a and also through the by-pass 0, so that such short movements oi the piston and cylinder in a direction toward each other are unrestrained. During ihc return movements of said parts the cl'icck-ralve closes on its scat, closing the by-pass c, consequently said return movements ol the parts are restrained.

\Vhcn the piston and cylinder are suddcnly inovcd unva-rd och other for a long distance, due to a violent shock, the piston moves. prcsmnahly, to or no: r the lower end of the cylindcr, .aud the chock-valve opens. and the movements are unrestrained until the piston passes the port rr', when the combined areas ot'l he ports leading from the lower eml-porl'ion oi" the cylinder being materially reduced, further movements of the parts are restrained, and when the piston pas es the portc and closes over a portion. of the port a". said movciucnlsmre still ii-urthcr z-eslraii'md, and so on until the piston passes all the ports, and at the end of a long stroke the piston is checked by a yielding cushion tormcdpt the lower end of the cylinder. Thus movements of the piston and cylinder in a direction toward each other are l l l l l unrestrained during the first part of the stroke, and more and more restrained during the last part thereof, until checked. On the return lnovcn'ients of the parts the checkvalve closes, but during the first part of said return movements they are unrestrained for the reason that the ports above and below the piston are open, permitting passage of the liquid, and such unrestrained movements of the parts continue until the piston closes the port 0, when the remaining portions of said return movements are severely restrained. It will be noted that the ports a, c and c" extend over a distance greater than the thickness of the piston thereby providing openings both above and below the piston.

In lieu of providing a triangular-shaped port (1,, as shown in Fig. 3, at the lower end of the bypass a, said port may be made as a parallel-sided slot, see Fig. i; and in lieu of providing the several ports 0, 0 ,0", at the lower end of the cylinder leading to the by-pass c, a similar parallel-sided slot may be employed, it being understood that I do not limit my invention to the shape or number of the ports at the lower end of the bypass 0 as long as they extend over a distance greater than the thickness of the piston.

Having thus described my invention, what I claintns new and desire to secure by Letters Patent is z--- 1. A shock-absorber comprising a cylinder and in'iperi'm'ate piston, said cylinder having two hy-passcs extending from endto end of it, each having a port at its upper end, and one having a port at its lower end, and the other having a series of ports at its lower end, the combined areas of which are as great as the area of the port atthe upper end of the bypass, the ports of said series being so arranged as to permit the piston to move over them sm-Zathn, whereby the areas of the ports below the piston gradually bccome less than the areas of the ports above the piston, including the port at the upper end of the by-pass, to restrain and finally check movement of the piston, a regulating-valve cordaincd in one of said bypasses, a valre-seatarranged in the other bypass and a check-valve movable toward and from said seat, substantially as described.

2. A shock-absorber comprising a cylinder and an imperforate piston, said cylinder having a bypass between its upper and lower ends, a chec rkwalve arranged in said by-p'ass pern'iitting unrestrained movement of the piston during the first part, of its down stroke and restrained movement thereof during the last part of its up stroke, the lower end portion of said by-passbeing in open communication with the cylinder for a distance greater than the thickness of the piston, whereby the area of open communication with the cylinder below the piston gradually bernmes less than the area above the piston as the piston moves in :1 downward (lirecti ni over the lower end portinn of tinhy-puss upon the occurrence vi :1 Vin- ]cnl slim-k, ihercliy gradually restraining;

ilu vnwzlrd movement of the piston more and more during the last part of its stroke and permitting unrestrained n'iovenient. of the piston duringthe first part of its return 11 rni'r :15 compared with the last part of its 10 return stroke, substantially as dessribed.

In testimony whereof, l hm'e signed my nannv to (his specification, in the presence Hf [W0 si'ihwriiiing. witnesses. f \CILLLXM BRUCE K'YAPP; 'itncsscs: E. J Ninjas, 1

- n. In. Inns. 

